1. Field of the invention
The present invention relates to a synthetic resin tube and a producing method thereof, and more particularly to a partially flexible tube which may be used as a drainpipe at a drainage facility of an overhead section of an expressway and a producing method thereof.
2. Description of Related Art
Conventionally, at beams and piers of an overhead section of an expressway, a plurality of straight tubelike drainpipes are used in order to lead rain water which is collected in a drainage tank provided at a road surface to sewerage. These water pipes are provided vertically and horizontally and are connected with each other by suitable connecting equipment.
However, since it is necessary to connect a plurality of straight drainpipes by connecting equipment such as elbows and bends which are suited for the situation of the construction site, the work of pipe arrangement is quite troublesome.
Particularly, when the water pipes are provided at a place which requires many curbs of the pipes, the work of pipe arrangement becomes further complicated, and accordingly, becomes inefficient.